Mineralogical differences

Gangas et al. (2) made a similar exploratory study of ancient Greek pottery. They prepared thin samples by scraping 200 mg from the insides of the pottery. They found that there were distinct differences in the spectra obtained which were correctable with archaeological evidence. Among four main groups of pottery examined, clear mineralogical differences were obtained for samples that were the same in appearance. 

The classification of chondrites on the basis of their elemental composition is recent with respect to the more traditional classification based on textural and mineralogical differences 6). In the case of carbonaceous chondrites this classification was revised by Wasson in 19747). The petrological type (from 1 to 6 even if some authors also use 7) is intended to indicate the degree of equilibration and metamor-phical recrystallisation. So 1 indicates the least-equilibrated and 6 the most-... 

Despite more than four decades of research, there is, as yet, no consensus in the silicosis literature for the fundamental reasons behind the different membranolytic activity of the various silica polymorphs and the other oxides. One possible reason for this slow progress is the neglect of mineralogical differences between the various phases, in terms of both chemistry and crystal structure, as reflected in the usage of terms such as quartz glass (sic) in the literature.12... 

In Chapter 5, Olin and Blackman explain that differences in the chemical compositions of pottery are caused by both the use of temper and by chemical and mineralogical differences in the source of the clay. Olin and Blackman report on the continuation of their studies of majolica (a common earthenware pottery) from the Spanish Colonial period in Mexico. They used INAA as well as microscopic examination of the minerals to show that majolica produced in Spain could be distinguished from that produced in Mexico. Volcanic temper was present in the ceramics produced in Mexico, and the chemical analysis of these local ceramics suggested different production centers in Mexico. The discovery of a chemically distinct group of sherds added to the typological classifications of this pottery. 

A second and more likely hypothesis to explain the variability in mineralogic composition of the suspended sediment over time stems from mineralogic differences at the surface. The different members of the Edwards Group outcrop across the aquifer, and each have subtly distinct clay mineralogies. Spatial variation in rainfall and differences in travel time could result in the appearance of these distinct sediment types at the spring at different times. 

The practical importance of carbon isotope analyses lies in the possibility to distinguish carbonates formed (or transformed) during migration and oxidation of hydrocarbons from sedimentary or other carbonates even in the absence of real mineralogical differences. 

Evangelou, V. P., and F. J. Coale. 1987. Dependence of the Gapon coefficient on exchangeable sodium for mineralogically different soils. Soil Science Society of America Journal 51, no. 1 68-72. 

The purpose of the preparatory processing of the raw materials is to convert these chemically and mineralogically different materials, usually supplied to the plant in coarse lumps, into raw meal or slurry of homogeneous composition. This has to be accomplished with suitably chosen machinery and methods, and at lowest possible cost, in order thus to fulfil the basic conditions for an economical burning process. 

Figure 5.16 demonstrates the effect of different mineralogy, different pore fluid and the presence of shale. 

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